Arkanoid.css example (from https://github.com/AlphaGit/random-javascript/blob/master/arkanoid-canvas/arkanoid.css)

arkanoid.css

/* from http://stackoverflow.com/questions/4288253/html5-canvas-100-width-height-of-viewport */

* {
    margin: 0;
	padding: 0;
}

html, body {
	width: 100%;
	height: 100%;
}

canvas {
	display: block;
}